Overview of the KSTAR Research Progress and Future Plan toward ITER and K-DEMO
a Ulsan National Institute of Science and Technology, Ulsan, b b a b Hyeon K. Park M.J. CHOI , S.H. HONG Y. In , Y.M. JEON , Korea J.S. Kob, W.H. Kob, J.G. KWAKb J.M. KWONb, J. b National Fusion Research Institute, Daejeon, Korea UNIST, Ulsan, Korea Leeb, J.H. LEEb, W. LEEb, Y.B. NAMd, Y.K. Ohe, c Seoul National University, Seoul, Korea b f g d CEA, St. Paul Lez Durance, France B.H. PARK , J.K. PARK , Y.S. PARK , S.J. e b c b h ITER Organization, Route de Vinon-sur Verdon. 13067 St. WANG , M. YOO , S.W. YOON , J.W. AHN , Paul Lez Durance, France On behalf of b f i b J.G. BAK , C.S. CHANG , W.H. CHOE , Y. CHU , f Princeton Plasma Physics Laboratory, Princeton, NJ, USA the co-authors and KSTAR Team J. CHUNGb, N. EIDIETISj, H.S. HANb, S.H. g Columbia University, NY, USA HAHNb, H.G. JHANGb, J.W. JUHNb, J.H. KIMb, h Oak Ridge National Laboratory, TN, USA i K. KIMh, A. LOARTEe, H.H. LEEb, K.C. LEEb, D. Korea Advanced Institute of Science and Technology, Daejeon, Korea th f c b b at 27 IAEA FEC, MUELLER , Y.S. Na , Y.U. NAM , G.Y. PARK , j General Atomics, CA, USA b e g K.R. PARK , R.A. PITTS , S.A. SABBAGH , k Pohang University of Science and Technology, Pohang, Gandhinagar, India, 2018 G.S. YUNk Korea IAEA FEC PARK - 1 - Topics to be addressed . Mission and role of the KSTAR research for ITER and K- DEMO . Advantages of tokamak plasma research on KSTAR . Progress of the KSTAR research program . High performance and steady-state operation . Physics of MHD/Turbulence . Progress and understanding of the ELM-crash control with RMP . Research efforts for ITER and K-DEMO . Future upgrade plan . Summary
IAEA FEC PARK - 2 - Mission and role of KSTAR for ITER and K-DEMO
KSTAR Mission is: • to explore science and technology for high performance steady-state operation, that are essential for fusion reactors K-DEMO Role of KSTAR for ITER & K-DEMO • Expansion of operating regimes, validation of tokamak physics and advanced control for SC device like ITER • Stationary High beta (흱N ~4) with high using the KSTAR unique tools bootstrap • Optional new mode of operation including to expand the KSTAR operation boundaries of the conventional modes of auto start-up with high duty cycle operation and new mode of operation for minimum harmful instabilities • CD and divertor heat flux control (avoid NTM and ELM-crash) to explore physics and preemptive control of the harmful instabilities in high beta operation (ELM-crash, NTM, disruptions, etc.) ITER to assist optimum operation of ITER: H-mode threshold power control, rotation control via NTV, heat dispersion with RMP, etc. • Exploration of the limit of high beta steady state operation and R&D of key engineering and technology for K-DEMO • Steady-state H-mode (흱N ~2) Exploration of higher beta operation with the KSTAR upgrade • Rotation by NTV, and new start-up, KSTAR H-mode access Alternative current drive for steady-state operation • Suppression of ELM-crash, New start-up for high duty cycle with long pulse disruption
IAEA FEC PARK - 3 - View of KSTAR with new NBI-2 system
ECH & Helicon & LHCD
KSTAR NBI-1
Advanced Microwave Imaging Diagnostics
Carbon wall NBI-2 (New)
IAEA FEC PARK - 4 - Collaborating domestic and international Institutes and Universities on the KSTAR program
Domestic Collaborating Domestic Collaborating Universities and Institutes Universities and Institutes
IAEA FEC PARK - 5 - Device parameters of KSTAR, ITER and K-DEMO
KSTAR KSTAR ITER K-DEMO Parameters (achieved) (Goals) (Baseline/SS) (Option II)
Major radius, R0 [m] 1.8 1.8 6.2 6.8 Minor radius, a [m] 0.5 0.5 2.0 2.1 Elongation, 2.16* 2.0 1.7 1.8 Triangularity, 0.8 0.8 0.33 0.63 Plasma shape DN, SN DN, SN SN DN (SN)
Plasma current, IP [MA] 1.0 2.0 15/ ~10 > 12 Toroidal field, B0 [T] 3.5 3.5 5.3 7.4 H-mode duration [sec] 73 300 400 / 1000 SS
N 3.0 (4.3, transient) 5.0 ~3.0 ~ 4.2 Bootstrap current, fbs ~0.5 ~ 0.6
Superconductor Nb3Sn, NbTi Nb3Sn, NbTi Nb3Sn, NbTi Nb3Sn, NbTi Heating /CD [MW] ~10 ~ 28 ~ 73 120 PFC / Divertor C, W C, W W W Fusion power, Pth [GW] ~0.5 ~ 3.0
* exceeded IAEA FEC PARK - 6 - Topics to be addressed
. Mission and role of KSTAR research . Advantages of tokamak plasma research on KSTAR . Progress of the KSTAR research program . High performance and steady-state operation . Physics of MHD/Turbulence . Progress and understanding of the ELM-crash control with RMP . Research efforts for ITER and K-DEMO . Future upgrade plan . Summary
IAEA FEC PARK - 7 - Uniqueness-1: nearly perfect symmetry of the tokamak plasmas
Extremely low magnetic ripple for minimum ripple loss. (B/B~0.05 %) -5 Extremely low error field configuration (훿B/B0~1x10 ) . Manufacturing and assembly of the magnets with high accuracy . Robust structures to sustain the TF coil shape uniform Designed with strong shaping capability for high beta operation stability . Double & single null capable and passive stabilizer for stabilizing VDE & RWM . Control flexibility using four pairs of CS coils and high elongation ( ~ 2.16) & triangularity ( ~ 0.8)
SC magnets manufactured without internal joints to minimize error field
IAEA FEC PARK - 8 - Uniqueness-2: Versatile in-vessel control coils for perturbation study and advanced imaging diagnostics
Unique in-vessel control coils with 3 poloidal rows KSTAR In-vessel (top, middle and bottom; e.g., ITER) Control Coils Top / Middle / Bottom . Flexible 3D field perturbation with n=1, 2 and mixed . Broad band power supply (~10 kHz) and patch panel for fast control for position, ELM-crash, rotation control & RWM control
Advanced 2D/3D imaging diagnostics . ECEI, MIR, BES, imaging bolometer, ECEI MIR Bolometer FILD, SXR, etc. . Enable us to access the dynamics of fundamental physics of MHD/ turbulence that were not available
IAEA FEC PARK - 9 - Topics to be addressed . Mission and role of KSTAR research . Advantages of tokamak plasma research on KSTAR . Progress of the KSTAR research program . High performance and steady-state operation . Physics of MHD/Turbulence . Progress and understanding of the ELM-crash control with RMP . Research efforts for ITER and K-DEMO . Future upgrade plan . Summary
IAEA FEC PARK - 10 - Effect of high toroidal rotation (or high edge rotation shear) on energy confinement in KSTAR
Toroidal rotation (Mi or torque) is a hidden parameter in energy Beam torque is linear with confinement scaling?? Mach number . Excellent correlation between the energy confinement time
(tth) and Mach number (Mi) or torque . L-mode and H-mode data can be combined with the rotation related parameter (turbulence physics basis?) MAST, Mi ~1. . Further study on edge shear, counter rotation, role of intrinsic Off-set value: rotation, etc. is in progress Intrinsic rotation S.G. Lee, EX/P7-4
J.S. Kang, NFRI High toroidal rotation speed in KSTAR may be due to nearly perfect tokamak plasma symmetry (low error field) H-mode L-mode Beam torque is linear with the Mach number (record high Mi~0.8)
Edge rotation shear and Er are well correlated with core rotation speed
Off-set value: Intrinsic rotation
(AU)
IAEA FEC PARK - 11 - NBI-heated long pulse H-mode operation (> 1 min)
Long pulse H-mode discharge with NBI & ECH
• Fully non-inductive advanced operation with high beta (N ~2.0, P ~2.5) was up to 20s. • H-mode was sustained over 70 s, BUT gradual performance degradation due to the heated limiter
In 2018 campaign, longer steady-state, fully non- inductive operation over ~100s will be attempted with upgraded - Active water cooling into PFC/Divertor - Boron powder dropper (PPPL / Gradual performance degradation ORNL collaboration) Due to increased wall recycling - Additional heating (NBI, ECCD)
0 10 20 30 40 50 60 70
IAEA FEC PARK - 12 - Exploring conventional and new operation modes for optimal scenarios applicable to ITER and K-DEMO
7
6
5 #16498
4 ITB foot
(keV) i 3 T (ρ=0.46) 2
1
0 400 ITB @2.5 s H-mode @4.5 s 300
200
(km/s)
t V 100
0 1.8 1.9 2.0 2.1 2.2 2.3 R (m) Search of alternative new mode of
Operation (combine ITB and low q95) . Broad ITB provides good confinement in the core
. Low q95 avoids harmful MHDs (e.g. NTM and ELMs) . Sawtooth can be used for particle control and q~1 surface can be controlled with CD. . Expense for MHD control (ELM and NTM) can be used for
additional CD due to reduced Fbs from H-mode
IAEA FEC PARK - 13 - Topics to be addressed . Mission and role of KSTAR research . Advantages of tokamak plasma research on KSTAR . Progress of the KSTAR research program . High performance and steady-state operation . Physics of MHD/Turbulence . Progress and understanding of the ELM-crash control with RMP . Research efforts for ITER and K-DEMO . Future upgrade plan . Summary
IAEA FEC PARK - 14 - Theoretical model for Sawtooth instability (Full or Partial)?
#18186 Direct q0 measurements (2015, 2016) alone cannot validate the model • During nearly four decades, there are two groups
of measurement; ~1.0 with calculated by M3DC1 with q >1.0 in MHD 0 0 q0~0.07 (J. Ko) quiescent time right after the crash • Time evolution of 3/3 2/2 1/1 further supports
q0>1.0 “Full reconnection model” by Kadomtsev is supported by the validation experiments
Growth rates of double tearing modes with the position of current Y. Nam, NF 2018 blip (M3DC1) IAEA FEC PARK - 15 - Magnetic island (2/1) can alter the electron heat transport by the flow and turbulence
Measured Te turbulence and apparent Magnetic island modifies the poloidal flow rotation around the 2/1 island and the 푻풆 turbulence around itself . Merging of turbulence near X-point and penetration to the island can cause “minor and major” disruption . Global XGC1 simulation shows that magnetic island makes an 2/1 electrostatic potential structure non- axisymmetric 퐸 × 퐵 flow perturbation (a) . gKPSP Micro-stability analysis shows that the 퐸 × 퐵 shear flow at near O-point is strong enough to suppress a significant portion of micro- instabilities (c)
J.M. Kwon, Phys. Plasmas (2018) M.J. Choi, NF (2017), EX/11-2 (oral) TH/8-1 (oral) IAEA FEC PARK - 16 - Exploring the physics of transport and transient instability using ECEI and MIR systems
Interaction of the ELMs and Solitary Observation of long range non- Quasi-coherent modes (QCMs) perturbation (SP: partial n=1 mode) diffusive “avalanche” event were observed in low- collisionality regime of KSTAR • SP appears ~ 100 흁s prior to crash • Voids and bumps in spatial Te fluctuations is shown in (a) ECH and ohmic discharges. • Opposite rotation due to Er x B drift • In ECH discharge, the increased • Symmetric corrugations in Te profile are shown in (b) and (c) Te/Ti by ECH injection seems to drive the QCM.
JE Lee, Scientific Report 2017 M. Choi, 4th UNIST-Kyoto J.H. Lee, POP (2018) Workshop (2018)
IAEA FEC PARK - 17 - Topics to be addressed . Mission and role of KSTAR research . Advantages of tokamak plasma research on KSTAR . Progress of the KSTAR research program . High performance and steady-state operation . Physics of MHD/Turbulence . Progress and understanding of the ELM-crash control with RMP . Research efforts for ITER and K-DEMO . Future upgrade plan . Summary
IAEA FEC PARK - 18 - Stable and robust ELM-crash control at ITER baseline operation conditions
n=1 full RMP under 360 degree rotation ELM-crash suppression state sustained with ELM-crash n=1, and RMPs (record ~34 s with n=1) suppressed condition is sustained under 3600 rotation at n=1 34 sec t RMP: owing to the wall low error fields in KSTAR? 3600 rotation
ELM-crash suppression is close to the Middle coils are very ITER baseline conditions (q ~3.4, and 3.0 kA/turn 95 important to get better βN~1.8) and reliable ELM- Mitigation Suppression crash suppression in KSTAR . Additional mid-RMP n=2, even (T/B) coil could provide n=2, even (T/M/B) more flexibility in + - + - + - + - - + - + control of the ELMs + - + - + - + - and rotation in ITER IAEA FEC PARK - 19 - Prediction and validation of the n=1 RMP operating window for the ELM-crash suppression in complex KSTAR coil configuration space
IM=0kA subspace (off-mid-plane only) J.K. Park, Nature Physics 2018 Offering excellent guidance to optimize new RMPs – such as “off- mid-plane” only n=1 RMP ELM suppression in KSTAR Various ELM suppression windows were successfully validated with dynamic RMPs
IT=IB=5kA subspace
IAEA FEC PARK - 20 - Role of turbulence induced by RMP and rotation (v⊥,ped ) in the ELM-crash suppression experiment Change of the turbulence amplitude (red box) and
v⊥,ped (blue box) as the RMP current ramp up and down (green) during ELM-crash suppression experiment: • Turbulence amplitude: Gradual increase and gradual decrease with a clear time delay with the RMP current ramp up and down – slow magnetic diffusion?
• Rotation (v⊥,ped ): Bifurcation? J.H. Lee, EX/P7-13 Poloidal coherence : Gradual increase in turbulence #19355 level along the field line through the ELM-crash phase, -mitigation, and -suppression phases Radial coherence : only at ELM-crash suppression phase – turbulence spread ? J.H. Lee, PRL, 2016 In early study, amplitude of the ELM (blue) during ELM-crash suppressed period is decreasing as the amplitude of turbulence (red) induced by the ramping RMP current (gold)
IAEA FEC PARK - 21 - Topics to be addressed . Mission and role of KSTAR research . Advantages of tokamak plasma research on KSTAR . Progress of the KSTAR research program . High performance and steady-state operation . Physics of MHD/Turbulence . Progress and understanding of the ELM-crash control with RMP . Research efforts for ITER and K-DEMO . Future upgrade plan . Summary
IAEA FEC PARK - 22 - Study of L/H transition Pth, NTV controlled rotation and divertor heat dispersion using RMPs
The effect of error fields on L-H transition Misaligned RMP configurations could be an threshold (Resonant B is more critical) alternative way to disperse the localized
19 -3 KSTAR, 0.6MA, 1.8T, q ~4.1, n = 2x1019m-3 KSTAR, 0.6MA, 1.8T, q ~4.1, n (10 m ) 95 e 95 e divertor heat flux n=1 n=2 B/B n=1(~2.7x10-4) + B/B n=2 1.6 0 0 1.6 NRMP n=1, -90p, n = 1.5~1.7 e . No electromagnetic cycling of the coils for n=2, 0p, n = 1.3 e 1.4 1.4 misaligned RMPs. Resonant B Non-resonant B
1.2 1.2
[MW]
[MW]
TH
TH
P 1.0 P 1.0 Y. In (oral) EX-7-1 broadening of wetted area 0.8 0.8 during RMP suppression 0 1 2 3 4 5 0 1 2 3 4 5 B/B (10-4) 0 I [kA/t]
W.H. Ko, APS 2017 NRMP .)
Rotation control with NTV a.u • Strong n = 2 field + ECH heating yields counter-Ip rotation in core, co-Ip rotation in outer region (first direct measurement of NTV) • Application to the ITER initial H-modes
(5 MA / 1.8 T) with ECH heating to ( fluxHeat Normalized increase edge rotation S. Sabbagh (Columbia U)
IAEA FEC PARK - 23 - Advanced shaping control and new start-up method for superconducting tokamak plasmas
Improved ITER baseline scenario with ITER Shape stability - ITER similar shape (ISS) high Standard Ip [MA] elongation up shape to 2.16 (design ~ 2.0) q95 ≈ 3.2 Vertically for high extended operation shape β ≈ 2 D. Mueller et al. APS 2017 N
Validation of Trapped N. Eidietis, APS 2017 Particle Configuration (TPC) for reliable ECH-assisted Comparison of a synthetic diagnostic of the Balmer-α line startup emission in the BREAK code • Robust startup method than the simulation considering the self- generated electric fields (a) conventional field null method with an experimental visible • Possible new automated start-up camera image (b)
J.W. Lee, NF 2017 IAEA FEC PARK - 24 - Topics to be addressed
. Mission and role of KSTAR research . Advantages of tokamak plasma research on KSTAR . Progress of the KSTAR research program . High performance and steady-state operation . Physics of MHD/Turbulence . Progress and understanding of the ELM-crash control with RMP . Research efforts for ITER and K-DEMO . Future upgrade plan . Summary
IAEA FEC PARK - 25 - New NBI-2 and Helicon CD systems for KSTAR
NBI systems (6 MW NBI-1 + 6 MW NBI-2) Helicon CD experiment and modeling • On-and Off-axis heating to get stable high beta operation • Prototype 500 MHz : 0.1 MW (‘16 ~’18) • Co-current direction in both NBI-1 & 2 (for CD & high rotation) • High power HCD (2 ~ 4 MW) • NBI-2: 6 MW, 100keV, 300 s (4MW off-axis + 2MW on-axis) • Klystron : 1 MW CW tube (5 units from SLAC) (‘19) • Power supply : 2 MW ready (‘19) • Schedule : 1 ion source (in 2018), 3 ion sources (in 2019) • Launcher : 2 MW (‘19) 1-D full wave modeling Perfect alignment 5.5 deg . NBI-1 NBI-2 (6 MW) (6 MW)
Current drive NBI-1 No dependency of coupling (A) (6 MW) on misalignment +/-3 degrees measured Slow wave coupling can NBI-2 (6 MW) Heating be ignored if polarization misalignment phi<5 푘 degrees ( ∥ ) 푘⊥
Prototype Helicon Antenna E.H Kim, PPPL IAEA FEC PARK - 26 - Time line of research and upgrade plan of KSTAR
2008 2017 Long-pulse H-mode research •Long pulse H-mode (>70s) •Alternative modes (ITB, low q, ..) First plasma Long-pulse Heating (ECH 84 GHz) (NBI~5.5 MW) •ELM research & control (>30s) (ECH~1 MW) •Fundamental physics validation
2018 2020 Advanced scenario & MHD research • Stable high beta operation
(N > 3.0, fBS > 0.5, Tion ~ 10 keV) Heating upgrade • Advanced mode develop. (hybrid, ITB, low q) (NBI ~ 12 MW) (ECH ~ 6 MW) • MHD & disruption control
2021 ~ 2023 ~ Steady-state & reactor mode research • Tungsten divertor & active cooling • Advanced current drive Divertor upgrade CD upgrade (HFS LHCD, Helicon CD, etc. ) (Tungsten divertor) (LHCD~4 MW) (Detached divertor) (Helicon CD~4 MW) • Steady-state operation (~300s)
IAEA FEC PARK - 27 - Summary
KSTAR is well engineered superconducting tokamak with unique tools for advanced research . Nearly perfect tokamak symmetry, intricate IVCC (top/middle/bottom) like ITER IVCC and advanced 2D/3D microwave imaging diagnostics Significant progress in expansion of operation regimes, validation of fundamental physics and ITER/DEMO relevant research . Long pulse H-mode (with ELM-crash) over 70s and ELM-crash suppressed H-mode over 30s . Expansion of conventional operating regimes (hybrid, high beta-P, ISS, High poloidal beta, ITB, low
edge q95, etc.) and exploration of new alternative mode for minimum harmful instabilities . Validation of fundamental physics: “full reconnection model” in sawtooth (1/1), Transport modification by turbulence and MHD in TM (2/1), design of optimum window for RMP field penetration, role of turbulence induced by RMP in ELM-crash suppression and turbulence physics (Avalanche and QCM) . ITER relevant research results: H-mode threshold power influenced by error fields, Rotation by NTV, Divertor heat dispersion by rotating RMPs, New start-up method, etc. Future upgrade plan with new ancillary systems . NBI-2 installation (2018~) and Helicon CD installation (2019~) . Upgrade plan (2021~) will be followed for actively cooled divertor and in-vessel components
IAEA FEC PARK - 28 - Thank you for your attention !
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